Exhaust gas recombustion assembly for an internal combustion engine

ABSTRACT

An internal combustion engine is provided with recombustion means which comprise a recombustion chamber case communicating with exhaust ports of the engine and secured to the engine housing. An outer case surrounding the recombustion chamber case is structured so that part of the outer case is integral with the engine housing, said integral part being formed by a portion of the engine housing which extends therefrom in the area surrounding the exhaust ports. Secondary air supplied to each exhaust port of the engine is warmed in an air chamber formed in the engine housing and located in the vicinity of the recombustion means.

[ 1 Aug. 12, 1975 United States Patent [191 Sasaki et al.

3,635,031 1/1972 3,665,71 1 5/1972 Muroki 3,703,083 11/1972 Tadokoro. 3,724,218 4/1973 EXHAUST GAS RECOMBUSTION ASSEMBLY FOR AN INTERNAL COMBUSTION ENGINE [75] Inventors: Yoshio Sasaki; Minoru Morita, both f N g y Japan Primary Examiner-Doug1as Hart Attorney, Agent, or FirmToren, McGeady and Stanger [57 ABSTRACT internal combustion engine is provided with 22 Filed:

[21] Appl. No.: 475,268

recombustion means which comprise a recombustion 0] F reign Application Priority Data chamber case communicating with exhaust ports of Dec 2] 1973 the engine and secured to the engine housing. An

outer case surrounding the recombustion chamber case is structured so that part of the outer case is integral with the engine housing, said integral part being formed by a portion of the engine housing which ex tends therefrom in the area surrounding the exhaust ports. Secondary air supplied to each exhaust port of 1 %O BO nw m m 1. 0 ZJ B 00 2 2 2 0 01 B 6 O 5 7 .9 726 5 oo 0 b2 3 2/ w mm 6 m mh "C n r H3 e U "S a 1 m m s. mfiw U IF N N 5 55 the engine is warmed in an air chamber formed in the engine housing and located in the vicinity of the recombustion means.

2,635,418 60/323 7 Claims, 4 r ing Figures PATEN] iii B 1 2W5 SHEET EXHAUST GAS RECOMBUSTION ASSEMBLY FOR AN INTERNAL COMBUSTION ENGINE BACKGROUND OF THE INVENTION This invention relates to internal combustion engines and particularly to those engines having recombustion means for recombusting the engine exhaust gas thereby to reduce harmful components contained therein.

Heretofore, exhaust gas recombusting means for internal combustion engines, which utilize secondary air in the recombustion process, have been assembled by means of welding or by a complicated bolted structure. The completed recombusting apparatus is then mounted on the engine body by means of flanges, or similar attachment means. As a result, the distance from the exhaust port of the engine to the recombusting means is considerably large, so that the exhaust gas from the exhaust port undergoes temperature reduction before it enters the recombusting means. This causes the reaction time in the recombustion chamber to be increased, so that it becomes necessary to increase the capacity of the recombusting means to compensate for the increased reaction time. Increasing the capacity of the recombusting means, however, requires larger flanges for installing the recombusting means on the engine body, so that the overall weight of the device is increased. Furthermore, where the recombusting means has a welded structure, the entire apparatus must be replaced if a component part requires replacement.

Particularly where the recombusting means is mounted on a rotary engine housing where component parts of the engine are closely mounted in vertical positions, the installation and removal of the recombusting apparatus will involve difficult operations. Also, in such a case, large and heavy flanges are required.

The present invention aims at providing solutions to the above problems, and it is an object of the invention to provide a compact internal combustion engine having recombusting means, in which a recombustion chamber case for recombusting the exhaust gas and communicating with the exhaust ports of the engine is secured directly to the engine housing. An outer case surrounds the recombustion chamber, and a substantially semicylindrical wall of the outer case covering substantially one half of the recombustion chamber case is formed from an integral part of the engine housing, with the rest of the outer case also having a semicylindrical shape and covering the rest of the recombustion chamber case being'secured to the aforementioned semicylindrical wall. Exhaust gas from each exhaust port is introduced through an associated exhaust gas inlet port into the recombustion chamber case, and the recombusted exhaust gas from the recombustion chamber is exhausted through an outlet provided in the scribed as an exhaust gas recombustion assembly for an internal combustion engine which includes an engine housing and exhaust gas outlet ports, said assembly comprising an inner casing defining an exhaust gas recombustion chamber and an outer casing surrounding the inner casing with the outer casing being partially formed from integrally extending wall portions of the engine housing. The inner casing is mounted directly upon the engine housing over the exhaust gas outlet ports to define the recombustion chamber in direct flow relationship with such outlet ports. Thus, an integral portion of the engine housing which is formed as a wall extending from the housing in the area surrounding the exhaust ports is utilized as part of the wall means defining the outer casing. Secondary air is supplied into the exhaust gas outlet ports and outlet means are provided for the recombustion chamber whereby the exhaust gases and the secondary air introduced directly from the exhaust ports into the recombustion chamber are recombusted with the products of such recombustion being discharged from the recombustion chamber through the outlet means.

The structure includes means defining an air chamber within the engine housing at a location proximate the recombustion chamber, said air chamber being in flow communication between the secondary air supply and the outlet ports whereby the secondary air introduced into the outlet ports may be preheated by passage through the air chamber.

Furthermore, the inner and outer casings may be arranged in a spaced relationship .defining an air gap therebetween, and the assembly may be provided with means for passing air through said air gap in order to maintain the inner casing at a desired temperature.

The outer casing may be formed in a double walled configuration containing insulation material therein.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

BRlEF DESCRlPTlON OF THE DRAWlNG FIG. 1 is a front elevation, partly broken away, of an internal combustion engine provided with a recombusting means according to the invention;

FIG. 2 is a plan view, partly broken away, showing the arrangement of HG. 1;

FIG. 3 is a front elevation, partly broken away, of another embodiment of an internal combustion engine provided with a recombusting means according to the invention; and

FIG. 4 is a plan view, partly broken away, showing the arrangement of FIG. 3.

DESCRIPTlON OF THE PREFERRED EMBODlMENTS Referring now to the drawings, wherein like reference numerals refer to similar parts throughout the various figures thereof, FIGS. 1 and 2 show an embodiment of the invention as applied to a reciprocating piston engine having an engine body 1 with a plurality of cylinders formed in its housing 2. Air-fuel mixture enters each cylinder through an intake port 4 formed in the housing 2 and intake valve 5, and the exhaust gas in the combustion chamber 3 is exhausted through exhaust valve 6 and exhaust port 7 also formed in the housing 2. The housing is provided with an elongated air chamber 8 extending in the direction of a row of exhaust ports 7. The air chamber 8 is communicated with each exhaust port 7 through an orifice 9. The housing 2 is also formed with an inlet port communicating with the air chamber 8, and secondary air is adapted to be supplied from an air pump 11 through the inlet port 10 to the air chamber 8, and thence through the orifice 9 to the associated'exhaust port 7. The housing also has mounts 12 surrounding the opening of the individual exhaust ports 7, and a recombustion chamber'case 16 is provided at a location spaced from the housing 2 by these mounts as will be described hereinafter. The housing 2 is also provided with an integral semicylindrical wall 13.

An exhaust gas guide sleeve 14 is fitted in each exhaust port 7, and a cylindrical support 15 is fitted on part of each exhaust gas guide sleeve extending from the exhaust port. 1

The recombustion chamber case 16, in which the exhaust gas is recombusted, consists of two semicylindrical inner shells 17 and 18, which are lapped edge to edge. The inner shell 18 is provided at, each end with a cylindrical member 19 closed at the outer end. The inner shell 17 is formed with the same number of openings 20 as the number of exhaust ports, with all openings 20 being fitted on the respective cylindrical supports 15 to support the recombustion chamber case 16.

Each cylindrical support 15 is held in position with the flange formed at its stem urged against the associated mount 12 by the portion of the inner shell 17 surrounding the associated opening 20. The inner shell 18 is provided at a portion centrally of its axial length with an exhaust gas outlet 21. This inner shell 18 is supported in a loosely restrained state bythe cylindrical members 19.

The recombustion chamber case 16 is surrounded by an outer case member 22, which is secured by bolts 23 to the semicylindrical wall 13. Support spacers 44 are provided between the inner shell 18 and outer case member 22 to regulate the disposition of the recombustion chamber case 16. The outer case member 22 is provided at each end with a cylindrical support 24 in which the associated cylindrical member 19 is supported.

The recombustion chamber case 16 is provided with an exhaust gas tube 25 mounted in the exhaust gas outlet 21 and extending through the outer case member 22. A portion of the exhaust gas tube 25 extending from the outer case member 22 is surrounded by an outer cylinder 26 secured to the outer case member 22. The outer case member 22 has a double wall structure consituted by two walls 27 and 28, and a heat insulation material 29 is provided in the space between the walls 27 and 28.

The assembly is structured so that an annular space 30 is defined between the recombustion chamber case 16 and the semicylindrical wall 13 and outer case member 22 surrounding the case 16. With this arrangement, the recombustion chamber case 16 is cooled by air flowing into the annular space 30 through an inlet 31 provided in the semicylindrical wall 13 and flowing out of the space 30 through an outlet 32 also provided in the semicylindrical wall 13.

With the construction described herein, the exhaust gas emitted to each exhaust port 7 in the operation of haust gas are combusted. Inthis case, the secondary air supplied-to the exhaust port 7 is warmed in the air chamber 8 which is located near the recombustion chamber case 16. Also, the exhaust gas from the exhaust port 7 can enter the adjoining recombustion chamber case 16 without being cooled.

The recombusted exhaust gas is dischargedfrom the recombustion chamber case 16 through the exhaust gas tube 25. Further, the air flowing through the annular space 30 prevents the recombustion chamber case 16 from being heated to too high a temperature, and the warm air from the annular space 30 may be usedfor other exhaust gas purifying means. t I

FIGS. 3 and 4 show another embodimentof the invention applied to a rotary engine 1'. Two peripheral walls 34,in which a rotor 33 executes planetary motion and which are joined togethervia an intermediate wall 35, are assembled together with endwalls 36 and 37 by means of tension bolts 38 to form an engine housing 2', with a combustion chamber 3' being formed within each peripheral wall. Each peripheral wall 34 is provided with an exhaust port 7' communicating with the combustion chamber 3', and with a mount 12 surrounding the opening of the exhaust port 7'. A recombustion case 16', to be more fully described hereinafter, is provided at a location spaced from the. housing by the mounts. The peripheral walls 34, intermediate wall 35 and end walls 36 and37 have respective semicircular walls which are joinedtogether to form a semicylindrical wall 13 surrounding the mounts 12'.

The engine housing 2 constituted by a plurality of walls is provided with an elongate air chamber 8 extending in the direction of axis of.revolution of the rotor 33. The air chamber 8.is located adjacenta lower portion of the semicylindrical wall 13' and arranged in flow communication with each exhaust port 7 through an orifice 9'. Secondary air isadapted to flow through an inlet port 10' into the air chamber 8' and is supplied therefrom through the orifice 9 to the associated exhaust port 7'. v v

An exhaust gas guide sleeve 14' is fitted in each exhaust port 7', and an inlet guide 39 is fitted on'part of each exhaust gas guide sleeve 14' extending from the exhaust port. Each inlet guide is provided at its stem with a flange, which is secured by bolts 41 to the associated mount 12' with a gasket 40 being inserted between the flange and mount. Fitted on each inlet guide 39 is a cylindrical support 15', which is formed at its stem with a flange similar to that of the inlet guide. The recombustion chamber case 16 consists of two semicylindrical inner shells 17' and 18 which are lapped edge to edge. These inner shells are assembled together with a .cylinder 43 constituting an exhaust gas duct 42 clamped between them at their one end. The inner shell 17' is formed with holes 20', which are located at positions corresponding to the respective exhaust ports'7' and are fitted on the respective cylindrical supports 15' tosupport the inner shell 17'. Theother inner shell 18' is supported by an outer case member 22' via support spacers 44 such that it is engaged edge to edge with the inner shell 17. i v

The outer case member 22' is engaged edge to edge with and secured to thefseir nicylindrical wall 13 by means of bolts 45. The outercase member 22' has a double wall structure constituted by two walls 27' and 28 with a heat insulating material 29' provided in the space between the walls 27 and 28'. A tube 46 forming outlet port 21 of the recombustion chamber case 16' is fitted in the aforesaid cylinder 43 and is supported by a support plate 47. The support plate 47 is mounted in an opening 48 formed at one end of the semicylindrical wall 13 and outer case member 22 and is secured by bolts 50 to that end, thus securing together the cylinder 43, tube 46 and a cover 49 surrounding the tube 46.

With this arrangement, an annular space 30' is defined between the recombustion chamber case 16' and the semicylindrical wall 13 and outer case member 22 surrounding the case 16, and the case 16 is cooled by air flowing into the annular space through an inlet 31 provided in the semicylindrical wall 13 and flowing out of the space 30 through an outlet 32' also provided in the semicylindrical wall 13.

With the above construction applied in an internal combustion engine having recombustion means, the exhaust gas exhausted to each exhaust port 7 in the operation of the engine is led together with secondary air admitted to the exhaust port 7 from the air chamber 8' through the associated orifice 9 to flow through the inlet guide 39 into the recombustion chamber case 16', where the harmful components in the exhaust gas are combusted. The recombusted exhaust gas is discharged through the cylinder 43 and tube 46. Here again, the exhausted gas and secondary air can enter the recombustion chamber case 16' without undergoing temperature reduction.

As has been shown, according to the invention the recombusting means is provided in the vicinity of the engine body, with the outer case surrounding the recombustion chamber case partly constituted by the engine housing, so that the exhaust gas from the exhaust port can enter the recombusting means without undergoing substantial temperature reduction. Thus, reactions of the harmful components in the exhaust gas can be effectively brought about in the recombusting means. Also, no large flange for mounting the recombusting means is required, so that a significant weight reduction can be achieved. Further, the installation and removal of the recombusting means is greatly facilitated. Still further, since the recombusting means is provided adjacent the engine body with the casing of the recombusting means partly constituted by the engine housing, it is possible to efficiently utilize the available space and greatly increase the capacity of the recombusting means, thereby enhancing the effectiveness of the reaction whereby harmful components are eliminated. Further, ready replacement of component parts of the recombusting means is possible. Since the air supplied to the recombusting means is warmed in the air chamber provided in the engine housing, adequate reaction of the exhaust gas can be ensured.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. An exhaust gas recombustion assembly for an internal combustion engine including an engine housing and exhaust gas outlet ports, said assembly comprising an inner casing defining an exhaust gas recombustion chamber, said inner casing being mounted directly upon said engine housing over said exhaust gas outlet ports to define said recombustion chamber in direct flow relationship with said outlet ports, an outer casing surrounding said inner casing, said outer casing being partially formed from integrally extending wall portions of said engine housing, means for supplying secondary air into said exhaust gas outlet ports, and outlet means for said recombustion chamber whereby exhaust gases and secondary air are introduced directly from said outlet ports into said recombustion chamber with recombusted exhaust gases being discharged therefrom through said outlet means.

2. An assembly according to claim 1 including an air chamber defined by said engine housing proximate said recombustion chamber in flow communication between said secondary air supply and said outlet ports, said air chamber operating to warm secondary air supplied to said outlet ports.

3. An assembly according to claim 1 wherein said inner and outer casings are arranged in a spaced apart relationship defining an air gap therebetween, said assembly further including means for passing air through said air gap for controlling the temperature of said inner casing.

4. An assembly according to claim 3 wherein said outer casing is structured in a double walled configura tion having insulating material enclosed therein.

5. An assembly according to claim 1 wherein said integrally extending wall portions of said housing comprise a generally concave configuration opening outwardly from said engine housing and extending therefrom along portions of said engine housing surrounding said outlet ports, said assembly further including an outer shell section mounted in sealed engagement with said integrally extending wall portions of said engine housing to define therewith said outer casing.

6. An assembly according to claim 1 wherein said inner casing is formed from a pair of shell sections, one of said shell sections having openings therein corresponding to the exhaust gas outlet ports of said engine housing and arranged to extend thereabout, the other of said shell sections being afflxed in sealing engagement with said one shell section to define said inner casing as extending generally across said engine housing to overlie and cover the exit orifices of said exhaust gas outlet ports.

7. An assembly according to claim 3 including support spacers located within said air gap to maintain said spaced relationship between said inner and outer casings and to support said casings relative to each other. 

1. An exhaust gas recombustion assembly for an internal combustion engine including an engine housing and exhaust gas outlet ports, said assembly comprising an inner casing defining an exhaust gas recombustion chamber, said inner casing being mounted directly upon said engine housing over said exhaust gas outlet ports to define said recombustion chamber in direct flow relationship with said outlet ports, an outer casing surrounding said inner casing, said outer casing being partially formed from integrally extending wall portions of said engine housing, means for supplying secondary air into said exhaust gas outlet ports, and outlet means for said recombustion chamber whereby exhaust gases and secondary air are introduced directly from said outlet ports into said recombustion chamber with recombusted exhaust gases being discharged therefrom through said outlet means.
 2. An assembly according to claim 1 including an air chamber defined by said engine housing proximate said recombustion chamber in flow communication between said secondary air supply and said outlet ports, said air chamber operating to warm secondary air supplied to said outlet ports.
 3. An assembly according to claim 1 wherein said inner and outer casings are arranged in a spaced apart relationship defining an air gap therebetween, said assembly further including means for passing air through said air gap for controlling the temperature of said inner casing.
 4. An assembly according to claim 3 wherein said outer casing is structured in a double walled configuration having insulating material enclosed therein.
 5. An assembly according to claim 1 wherein said integrally extending wall portions of said housing comprise a generally concave configuration opening outwardly from said engine housing and extending therefrom along portions of said engine housing surrounding said outlet ports, said assembly further including an outer shell section mounted in sealed engagement with said integrally extending wall portions of said engine housing to define therewith said outer casing.
 6. An assembly according To claim 1 wherein said inner casing is formed from a pair of shell sections, one of said shell sections having openings therein corresponding to the exhaust gas outlet ports of said engine housing and arranged to extend thereabout, the other of said shell sections being affixed in sealing engagement with said one shell section to define said inner casing as extending generally across said engine housing to overlie and cover the exit orifices of said exhaust gas outlet ports.
 7. An assembly according to claim 3 including support spacers located within said air gap to maintain said spaced relationship between said inner and outer casings and to support said casings relative to each other. 